Chemical segregation of complex organic O-bearing species in Orion KL

Tercero, B.; Cuadrado, S.; López, Alicia; Brouillet, N.; Despois, D.; Cernicharo, J.

doi:10.1051/0004-6361/201834417

Cited by 54 publications

(67 citation statements)

References 52 publications

(90 reference statements)

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“…We note that t-C 2 H 5 OCH 3 was tentatively detected in several high-mass sources, such as W51 e1/e2 (Fuchs et al 2005), which was refuted by Carroll et al (2015) and Orion KL (Tercero et al 2015). Later, Tercero, B. et al (2018) confirmed the detection towards the Orion KL compact bridge region. The last study reported a rotational temperature of 150±20 K and a column density of 3.0 ± 0.9 × 10 15 cm −2 , leading to an abundance of 3.7 × 10 −9 with respect to H 2 .…”

Section: New Detectionssupporting

confidence: 78%

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

Manigand

Jørgensen

Calcutt

et al. 2020

A&A

128

154

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Context. Complex organic molecules are detected in many sources in the warm inner regions of envelopes surrounding deeply embedded protostars. Exactly how these species form remains an open question.Aims. This study aims to constrain the formation of complex organic molecules through comparisons of their abundances towards the Class 0 protostellar binary IRAS 16293-2422. Methods. We utilised observations from the Atacama Large Millimetre/submillimetre Array (ALMA) Protostellar Interferometric Line Survey (PILS) of IRAS 16293-2422. The species identification and the rotational temperature and column density estimation were derived by fitting the extracted spectra towards IRAS 16293-2422 A and IRAS 16293-2422 B with synthetic spectra. The majority of the work in this paper pertains to the analysis of IRAS 16293-2422 A for a comparison with the results from the other binary component, which have already been published. Results. We detect 15 different complex species, as well as 16 isotopologues towards the most luminous companion protostar IRAS 16293-2422 A. Tentative detections of an additional 11 isotopologues are reported. We also searched for and report on the first detections of methoxymethanol (CH 3 OCH 2 OH) and trans-ethyl methyl ether (t-C 2 H 5 OCH 3 ) towards IRAS 16293-2422 B and the follow-up detection of deuterated isotopologues of acetaldehyde (CH 2 DCHO and CH 3 CDO). Twenty-four lines of doubly-deuterated methanol (CHD 2 OH) are also identified. Conclusions. The comparison between the two protostars of the binary system shows significant differences in abundance for some of the species, which are partially correlated to their spatial distribution. The spatial distribution is consistent with the sublimation temperature of the species; those with higher expected sublimation temperatures are located in the most compact region of the hot corino towards IRAS 16293-2422 A. This spatial differentiation is not resolved in IRAS 16293-2422 B and will require observations at a higher angular resolution. In parallel, the list of identified CHD 2 OH lines shows the need of accurate spectroscopic data including their line strength. Article number, page 2 of 31 S. Manigand et al.: Inventory of complex organic molecules towards IRAS 16293-2422 A Notes. (a) e 0 , o 1 and e 1 corresponds to the three first torsional states. The notation of the quantum numbers is directly taken from Mukhopadhyay (2016). (b) This corresponds to the number indicated in the top-right corner of each panel in Figures D.1 and D.2. (c) W is the integrated intensity of the unblended lines, summed over the range [ν 0 − ∆ν FWHM , ν 0 + ∆ν FWHM ], given ∆ν FWHM = ν 0 FWHM c , with FWHM equal to 2.2 and 0.8 km s −1 for IRAS 16293A and B, respectively.

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Section: New Detectionssupporting

confidence: 78%

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

Manigand

Jørgensen

Calcutt

et al. 2020

A&A

128

154

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“…This will allow us to select the important chemical paths between species and possibly constrain the chemistry of COMs. Recently, Tercero et al (2018) have suggested segregation of various O-bearing COMs based on spatial variation inside BN-KL. Including the channel information presented in this work, combined with quantitative estimates, which require the inclusion of zero-spacing data that is not yet available, will allow us to follow the abundance variations of each species along the expanding paths and better understand the chemistry in hot cores, both in the gas phase and on grain surfaces.…”

Section: Discussionmentioning

confidence: 99%

The complexity of Orion: an ALMA view

Pagani

Bergin

Goldsmith

et al. 2019

A&A

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The chemistry of complex organic molecules in interstellar dark clouds is still highly uncertain in part because of the lack of constraining observations. Orion is the closest massive star-forming region, and observations making use of ALMA allow us to separate the emission regions of various complex organic molecules (COMs) in both velocity and space. Orion also benefits from an exceptional situation, in that it is the site of a powerful explosive event that occurred ∼550 years ago. We show that the closely surrounding Kleinmann-Low region has clearly been influenced by this explosion; some molecular species have been pushed away from the densest parts while others have remained in close proximity. This dynamical segregation reveals the time dependence of the chemistry and, therefore allows us to better constrain the formation sequence of COMs and other species, including deuterated molecules.

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“…In contrast, only the first two vibration states (HC 3 N, v 7 = 2 and H 13 CCCN, v 7 = 1, HC 13 CCN, v 7 = 1 and HCC 13 CN, v 7 = 1 ) were tentatively detected towards AFGL 4176. Tercero et al (2018) also investigate the inventory of complex molecules towards Orion KL, this timed focussing on O-bearing species. With a resolution of ∼1.5 , they probe spatial scales of ∼620 au.…”

Section: Comparison With the High-mass Star-forming Regions Inmentioning

confidence: 99%

“…With a resolution of ∼1.5 , they probe spatial scales of ∼620 au. Tercero et al (2018) derive molecular abundances at three locations. These are selected based on where each of the species methylformate, ethylene glycol, and ethanol peak.…”

Section: Comparison With the High-mass Star-forming Regions Inmentioning

confidence: 99%

“…To date, the chemical inventory of only a handful of sources has been extensively studied with interferometers. These include the low-mass protobinary system IRAS 16293-2422(hereafter IRAS 16293, Jørgensen et al 2016 and the high-mass, starforming regions associated with Sgr B2(N) (Belloche et al 2016) and Orion KL (Brouillet et al 2013;Pagani et al 2017;Favre et al 2017;Tercero et al 2018;Peng et al 2019). Therefore, there is a substantial need for the continued investigation of additional hot cores in order to build up a database of the molecular inventories and temperatures characterising these sources.…”

Section: Introductionmentioning

confidence: 99%

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Molecular complexity on disc scales uncovered by ALMA

Bøgelund

Barr

Taquet

et al. 2019

A&A

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Context. The chemical composition of high-mass protostars reflects the physical evolution associated with different stages of star formation. In addition, the spatial distribution and velocity structure of different molecular species provide valuable information on the physical structure of these embedded objects. Despite an increasing number of interferometric studies, there is still a high demand for high angular resolution data to study chemical compositions and velocity structures for these objects. Aims. The molecular inventory of the forming high-mass star AFGL 4176, located at a distance of ~3.7 kpc, is studied in detail at a high angular resolution of ~0.35′′, equivalent to ~1285 au at the distance of AFGL 4176. This high resolution makes it possible to separate the emission associated with the inner hot envelope and disc around the forming star from that of its cool outer envelope. The composition of AFGL 4176 is compared with other high- and low-mass sources, and placed in the broader context of star formation. Methods. Using the Atacama Large Millimeter/submillimeter Array (ALMA) the chemical inventory of AFGL 4176 has been characterised. The high sensitivity of ALMA made it possible to identify weak and optically thin lines and allowed for many isotopologues to be detected, providing a more complete and accurate inventory of the source. For the detected species, excitation temperatures in the range 120–320 K were determined and column densities were derived assuming local thermodynamic equilibrium and using optically thin lines. The spatial distribution of a number of species was studied. Results. A total of 23 different molecular species and their isotopologues are detected in the spectrum towards AFGL 4176. The most abundant species is methanol (CH3OH) with a column density of 5.5 × 1018 cm−2 in a beam of ~0.3′′, derived from its 13C-isotopologue. The remaining species are present at levels between 0.003 and 15% with respect to methanol. Hints that N-bearing species peak slightly closer to the location of the peak continuum emission than the O-bearing species are seen. A single species, propyne (CH3C2H), displays a double-peaked distribution. Conclusions. AFGL 4176 comprises a rich chemical inventory including many complex species present on disc scales. On average, the derived column density ratios, with respect to methanol, of O-bearing species are higher than those derived for N-bearing species by a factor of three. This may indicate that AFGL 4176 is a relatively young source since nitrogen chemistry generally takes longer to evolve in the gas phase. Taking methanol as a reference, the composition of AFGL 4176 more closely resembles that of the low-mass protostar IRAS 16293–2422B than that of high-mass, star-forming regions located near the Galactic centre. This similarity hints that the chemical composition of complex species is already set in the cold cloud stage and implies that AFGL 4176 is a young source whose chemical composition has not yet been strongly processed by the central protostar.

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Chemical segregation of complex organic O-bearing species in Orion KL

Cited by 54 publications

References 52 publications

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

The ALMA-PILS survey: inventory of complex organic molecules towards IRAS 16293–2422 A

The complexity of Orion: an ALMA view

Molecular complexity on disc scales uncovered by ALMA

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